If the 606 is like the 603 which it seems to be, a prechamber tool is needed to pull them. Look at it this way the head has to come off anyway so try everything that you can to avoid it. With the prechamber out anything that has fallen into the cylinder can probably be blown out with compressed air. I would think that drilling the plug would weaken it enough to allow the prechamber to snap it as you take the chamber out. You may need a new prechamber but their under $100 last time I checked.

I don't know I am just throwing out every idea I can think of in the hope that one would help. Next week I am helping W140 S600 do this job on his 98, it looks very similer to my 603 everything is in about the same place.

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